package demo1;

import java.util.*;

public class Solution {


    int n ;
    boolean[] vis = new boolean[210];

    public int citys (ArrayList<ArrayList<Integer>> m) {
        n = m.size();

        int ret = 0;
        for(int i = 0; i < n; i++){
            if(!vis[i]){
                ret++;
                dfs(m, i);
            }
        }
        return ret;
    }

    public void dfs(ArrayList<ArrayList<Integer>> m, int pos){
        vis[pos] = true;

        for(int i = 0; i < n; i++){
            if(m.get(pos).get(i) == 1 && !vis[i]){
                dfs(m, i);
            }
        }
    }
}
